Problem with diseqc 1.2 motorised dish

I'm re-assembling my motorised dish. I had already prepare the cable from the receiver to the dish location some time ago. There are about 45 m of cable

Now i am facing a problem:

If ionly have the cable that comes from the receiver connected to the motor, it works fine. As soon as I connect the cable that goes to the Lnb, the motor stops rotating (it has an initial impulse and stops).

I tested with another cable exactly the same (length and brand) and the motor works normally (even with the Lnb on). The first thing that occurred to me was that I damaged the cable during the process of passing it through the pipes in the wall. But this theory leaves me a bit on the back foot:

After having pointed the dish at a satellite with the test cable, I have exactly the same signal with the 2 cables.

If the cable was damaged to rotate the antenna, I expected to have some signal loss too?! that I don't have...

If it's a damaged cable problem, how come it only manifests when I plug in the Lnb cable?!

I tested all connections and F plugs... the problem is not there.

Changing the cable will be complicated due to the gutters and pipes and it's possible that I'm missing something basic.

Any tips?

Thanks and sory for my english!

Quote from jenseneverest

Using a multimeter check for resistance in both of the inner and outer cable part's. Compare these to the other cable as well.

45 meters is a long run indeed.....possibly too long tbh.

The cable dose not like to be streached or bent in sharp angles.

BTW are you testing with the same receiver?

Thanks for you answer!

Tested with same receiver. All components were the same except the receiver-motor cable.

45m is really a lot but it works well with the test cable!

I don't have a multimeter... I'll try to get one.

Quote from mouadhada

Try to test with increase voltage option on lnb configuration !

Quote from thecrazybandit

I use a 30mtr run of cable and lose about 10% signal i think with a 45mtr run you are losing signal and voltage

Thanks for your time and answer!!

It was a damage in the cable! When i change it everything starts working ok!

And yes, I need voltage increased for motor works... it is a lot of cable!!